Bats are the only mammal that can fly. They have a furry body, and their wings are covered by smooth, flexible skin. Most species of bats live in attics, caves, or other sheltered places. Some species live in trees. Bats seem uncommon in many regions because they roost in dark places and come out only at night, when most people are asleep. Bats hang upside down when they are resting.

There are more than 900 species of bats - they live in all parts of the world except Antarctica and the Arctic. Most kinds make their home in the tropics, where they can find food the year around.